Tungsten-base alloy



Dec. 7, 1965 ULTIMATE TENS/LE STRENGTH, I000 psi v. R. THOMPSON ETAL 3,222,165

TUNGSTEN-BASE ALLOY Filed Oct. 11, 1963 I I I I I l I I l I I I I I I l I TEMPE RA TURE "F.

INVENTORS. VERNON R. THOMPSON and ROBERT C. WESTGREN By 2 g. H

' Age/1 United States Patent M 3,222,166 TUNGSTEN-BASE ALLOY Vernon R. Thompson, Greentree, and Robert C. Westgren, Pittsburgh, Pa., assignors to CrucibleSteel Company of America, Pittsburgh, Pa., a corporation of New Jersey Filed Oct. 11, 1963, Ser. No. 315,643 4 Claims. (Cl. 75-176) This invention relates to metal for use at high temperatures, such as about 3500 F., and in particular to metal having a desirable combination of very high strength together with good tensile ductility at such high temperature.

In brief summary, the ends of the invention are obtained by alloying with tungsten and about to 15% of columbium, small amounts of zirconium and carbon, and if desired, a small amount of vanadium.

A heat was made containing 0.19% carbon, 10.7% columbium, 0.14% zirconium, and the balance tungsten. When tested at 3500 F., this alloy exhibited a tensile strength of 49,000 p.s.i., an elongation in 0.5 inch of 42%, and a reduction of area of 64%. These results may be compared with those for an alloy consisting essentially of 88% tungsten and 12% columbium, which when tested at 3500 F. exhibited a tensile strength of 27,000 p.s.i., an elongation in 0.5 inch of less than 1%, and a reduction of area of less than 1%.

An additional heat was prepared, containing 0.07% carbon, 12.6% columbium, 0.29% vanadium, 0.12% zirconium, and the balance tungsten. When tested at 35 00 F., this alloy exhibited a tensile strength of 57,000 p.s.i., 43% elongation in 0.5 inch, and 52% reduction of area.

An idea of the improvement obtained with the invention may be had from the attached figure, wherein ultimate tensile strength is plotted against temperature for various high-temperature material. Curves 1, 2, 3 and 4 represent known high-temperature materials:

Curve 1 represents the results with a commercial alloy consisting essentially of about 0.5% titanium, balance molybdenum;

Curve 2 represents the results with an alloy consisting essentially of tungsten, balance tantalum;

Curve 3 represents the results with a commercial alloy designated TZM, containing about 0.5% titanium, 0.07% zirconium, and balance molybdenum; and

3,222,165 Patented Dec. 7, 1965 Curve 4 represents the results with a commercially pure tungsten.

Points 5, 6 and 7, represent the high-temperature alloys of another invention, described and claimed in co-pending application Serial No. 263,619, filed March 7, 1963. Point 8 represents the basis composition used above for comparison (10.3% columbium, 0.0054% carbon, 0.0009% oxygen, less than 0.0001% nitrogen, 0.0008% hydrogen, balance tugsten). Point 9 represents the 3500 F. strength of relatively pure tungsten (0.0014% carbon). It will be observed that point 8 amounts to substantially the same thing as the points 5, 6, and 7: an essentially carbon-free solid-solution-strengthened al 103/ with a tungsten base. Points 10 and 11 comprise examples of the invention, corresponding to the results of the 3500 F. tensile tests indicated above.

The alloys were made by concurrently consumableelectode vacuum-arc melting electrodes consisting of a solid tungsten rod and a columbium tube filled with tungsten carbide powder and Wires of zirconium alone or with Wires of vanadium.

We claim:

1. An alloy consisting essentially of about 0.005 to 0.20% carbon, about 5 to 15% columbium, about 0.05 to 1.0% zirconium, up to about 2% vanadium, balance essentially tungsten.

2. An alloy consisting essentially of about 0.02 to 0.20% carbon, about 5 to 15 columbium, about 0.05 to 0.3% zirconium, up to about 0.4% vanadium, balance essentially tungsten.

3. An alloy consisting of about 0.005 to 0.20% carbon, about 5 to 15% columbium, about 0.05 to 1.0% zirconium, up to about 2% vanadium, balance essentially tungsten.

4. An alloy consisting of about 0.02 to 0.20% carbon, abount 5 to 15% columbium, about 0.05 to 0.3% zirconium, up to about 0.4% vanadium, balance essentially tungsten.

References Cited by the Examiner UNITED STATES PATENTS 2,947,624 8/ 1960 Semchyshen -17 6 3,113,863 12/1963 Chang 75-174 3,116,145 12/1963 Semchyshen 75-176 DAVID L. RECK, Primary Examiner. 

1. AN ALLOY CONSISTING ESSENTIALLY OF ABOUT 0.005 TO 0.20% CARBON, ABOUT 5 TO 15% COLUMBIUM, ABOUT 0.05 TO 1.0% ZIRCONIUM, UP TO ABOUT 2% VANADIUM, BALANCE ESSENTIALLY TUNGSTEN. 